Escapement device for paper carriages of typewriters



ESCAPEMEN' DEVICE FOR PAPER CARRIAGES OF TYPEWRITERS Filed May e, 1953 ATToRN Patented July 7, 1936 V PATENT OFFICE ESCAPEMENT DEVICE FOR PAPER CAR- RIAGES OF TYPEWRITERS Fritz Eibert, Munich, Germany, assignor to f Robert Wolff, Basel, Switzerland Application May 6, 1933, Serial No. 669,706

In Germany November 26, 1932 10 Claims.

The inventionrelates to an escapement device for paper carriages of type-writers.

In the well-known escapement devices for paper carriages of type-Writers,.the type reaches the platen at the-.moment, at which a change fromthe retaining tothe displacement-.pawl in front of the retained-.tooth of theratchet'wheel occurs. change` does not..take.place without any movementand vibration of thepaper carriage so-thatthe `stroke of the type does not v occur during a periodzinwhich thepaper-carriage is absolutely ata standstill.` Consequently, .the impression. ofthe type is not sharp and the spaces-between the letters-become uneven according to whether-thetouch of the key is weak,

- strong, slow vor quick.

A further essential disadvantage-consists in the fact that the ratchetwheel rwhich moves by the action of the return main spring, strikes with its teeth on leavingthe reta'ining-pawl, `on to an inclined surface of the-displacement-pawl and `thereby offers a resistance to .the operated typelever immediatelybefore the impression of-.the

In order to avoida ydiminution in the force type. Vof the stroke, a .stronger touch on the keys is necessary forovercoming. this resistance, which in time tires the operator.

./The present inventioniavoidsthese disadvantages by. an escapement device which makes any vibration or movement of the paper carriage impossible before and during the stroke ofthe type, and, moreover, offersv no resistance to the operated type-lever.

. These advantages are aceomplishedinsuch a waythat a=paw-l which retains the..paper carriage in vitsinitial -position before every. touch of the key, remains` incontact with-.the tooth of the escapement device duringthe period of the forward. movement of the type-lever, up to the completed stroke oftheV type, land that this contact tooth after the lstroke ofithegftype on theplaten can ralsoi'be obtained by provid-ing the universal bar with aweight Which continues in its movei' ment after-thebar has come-to a standstill and 55acts thereby upon -.thepawl-bearer or-upon the retaining-pawl in such a manner that the retained tooth is released.

In` order to bring back into their initial posi- `tion all parts moved in the one direction by a touchon the key without any spring action being necessary, the inclined surface of the displacement-pawl is arranged in such a manner that the tooth which strikes this inclined surface afterbeing released by the retaining-pawl, acts Vonthe .pawl-bearer and thereby on all such parts as are moved by the touch on the key and returns the vpartsinto their initial position.' The tooth released by the pivotal retaining-pawl, strikes with force onto the inclined surface of the displacement-pawl so that the returnmovement of all parts, including the operated type-lever, oc-

-.curs. with considerably increased rapidity. By

this means the speed of type-writing is increased and the striking of the types one upon the other is prevented. The touch of the keys becomes lighter and the power v of impression greater. Additionally, the escapement mechanism is exposedV to less wear and interruptions are avoided to a large extent.

It is of advantage to limit the movement of the operating-lever in order that the movement will ceasewhen the type-lever with its type has just Yabout reached the printing point.` The remaining short movement up to the spot of impression can be effected by the type-lever by its own motor force, as it cannot be met by any impediments by the l escapement -mechanism, for the toothed wheel remains completely locked until after the impression of `the type-has taken place, and any influence onv the part ofthe return spring is prevented for the time being.

. Inthe drawing in which several examples are diagrammatically shown, is,

. Figure 1 an escapement device in which the retaining-pawl is pivotally arranged on the pawlbearer,

Figure 2 a plan-view of the pawl-bearer with the retaining-pawl and displacement-paw] in cross-section;

Figure 3 illustrates a modified embodiment of 4the invention.

, In the various illustrations, similarparts are designated by the same references.

When the key is o-perated, the type-lever A is set in motion by the well-known connection, and .strikes with its. head B against the universal-bar l. In yFigure l, the universal-bar I, is pivotally mounted on the axis 2. The lug 4 is a part of the universal-bar I. and is pivotally arranged at 3.

I is movably mounted on the axis 8. The stop of the pawl-bearer 'I is delimited by the set-screws 9 and IU. The retaining-pawl I2 is mounted on the pawl-bearer '1, the former being pivotally mounted on its axis I 3, and is loaded with a. weight I4. The displacement-pawl I5 having an inclined surface, is also fixed on the pawl-bearer 1. II is a tooth of the ratchet Wheel. A spring I6 serves the purpose of holding the universalbar in its initial position. The pawl-bearer 'I is kept in its initial position by the spring I'I, and the pivotal pawl I2 is kept in its initial position by a spring I8.

The action of the arrangement according to Figure l is as follows:

When the type-lever A is operated, it moves the universal-bar I in the direction of the arrow. After a certain movement of the type-lever, the universal-bar I strikes with its abutment 5 against the screw 6 of the pawl-bearer 1, the movement of which can be delimited by the setscrews 9 and I0. When the pawl-bearer in its movement strikes upon the set screw 9, the tooth II of the ratchet wheel still touches at this moment with a small part the retaining-pawl I2, being pivotally arranged on its axis I3.

After the universal-bar I and the pawl-bearer 'I has come to a. standstill, the retaining-pawl I2 continues its movement by means of its weight I4, thereby releasing the tooth II of the ratchet wheel. The tooth I I then strikes with force onto the inclined surface of the displacement pawl I5. By this means, all parts set into action by the touch of the key as well as the type-lever are moved back into their initial position.

In the arrangement shown in Figure 3, the pawls I2 and I5 are directly connected with the universal-bar I, whereby the retaining-pawl I2 is pivotably arranged. The type-lever A forced against the platen of the type-writer moves the universal-bar I for such a distance that the bar with its abutment 22 strikes upon an abutment 2|. This movement is shared by all parts arranged on the universal-bar. However, the tooth II of the ratchet wheel has not been set free from the retaining-pawl I2 by this movement. As, however, the retaining-pawl I2 with the aid of its weight I4 continues its movement around its axis i3, the tooth I I of the ratchet wheel is released. The tooth I! strikes upon the inclined surface of the displacement-pawl I5 lying before it, and by this means forces the universalbar and the operated type-lever back into its initial position. A spring I 8 holds the retainingpawl I2 in its initial position.

What I claim is:-

1. In an escapement device for the paper carriage of a typewriter, the combination which comprises means for retaining said paper carriage including a ratchet having teeth associated with said carriage and a removable and weighted retaining pawl, said retaining pawl being capable of limited movement on actuation of a type and of engaging a tooth of said ratchet up to completed impression of a type and due to its inertia imparted by said weight being capable of continuing its movement and of disengaging said tooth after said type has been impressed.

2. In an escap-ement device for the paper carriage of a typewriter, the combination which comprises a ratchet having teeth associated with said paper carriage, means for retaining said paper carriage including a movable retaining pawl being capable of limited movement on the actuation of a type and of engaging a tooth of said ratchet up to completed impression of said type, and having sufficient inertia to cause continuation of its movement and to disengage said tooth after said type has been impressed, and means for returning said pawl into its initial position.

3. In an escapement device for the paper carriage of a typewriter, the combination which comprises a ratchet having teeth associated with said paper carriage, means for retaining said paper carriage including a movable retaining pawl being capable of lirnited movement on the actuation of a type and of engaging a tooth of said ratchet up to completed impression of said type, and having sufficient inertia to cause continuation of its movement and to disengage said tooth after said type has been impressed, and means for returning said retaining pawl into its initial position, said returning means including a displacement pawl operatively associated with said retaining pawl and having an inclined surface adapted to slidingly receive said disengaged tooth.

4. In an escapement device for the paper carriage of a typewriter, the combination which comprises a universal bar adapted to be actuated by a type lever of the typewriter during a stroke thereof, a movable pawl bearer adapted to be acted upon by the forward movement of said universal bar during a stroke of the type lever, a retaining pawl pivotally mounted on said pawl bearer engaging a tooth associated with the carriage of the typewriter, said retaining pawl having suilcient inertia to continue its movement after the completion of the forward movement n of the universal bar and to disengage the tooth after completion of the stroke of the type lever, and a displacement pawl mounted on said pawl bearer having an inclined surface adapted to slidingly receive said disengaged tooth and to return said pawl bearer and said retaining pawl into their initial position.

5. In an escapement device for the paper carriage of a typewriter having types and a universal bar, the combination which comprises a ratchet having teeth associated with said paper carriage, a retaining pawl pivotally mounted on said universal bar, said retaining pawl being capable of limited movement on actuation of said universal bar by impression of a type and of engaging a tooth of said ratchet up to completed impression of a type, and having sufcient inertia to cause continuation of its movement and to disengage said tooth after said type has been impressed.

6. In an escapement device for the paper carriage of a typewriter having types and a universal bar, the combination which comprises a ratchet having teeth associated with said paper carriage, a retaining pawl pivotally mounted on said universal bar, said retaining pawl being capable of limited movement on actuation of said universal bar by impression of a type and of engaging a tooth of said ratchet up to completed impression of a type, and having sufficient inertia to cause continuation of its movement and to disengage said tooth after said type has been impressed, and a displacement pawl rigidly mounted on said universal bar and having an inclined surface adapted to slidingly receive said disengaged tooth and to return said universal bar and said retaining pawl into their initial position.

7. An escapement device for typewriters and the like which comprises a universal bar adapted to be operated on by a. type lever of the typewriter during a stroke thereof, a movable pawl bearer Cal adapted to be acted upon by the forward movement of the universal bar during a stroke of the type lever, a retaining pawl pivotally mounted on said pawl bearer engaging a tooth associated with the carriage of the typewriter said retaining pawl having suiiicient inertia to continue its movement after the completion of the forward movement of the universal bar whereby the tooth is released after the completion of the stroke of the type lever.

8. In an escapement device for typewriters having a universal bar operatively associated with a type lever and a ratchet wheel having teeth, the improvement which comprises a reciprocating retaining pawl successively engaging said teeth adapted to be acted upon by the forward movement of the said universal bar during a stroke of the type lever and to continue its forward movement after the completion of the forward movement of the said universal bar whereby a tooth is released by the retaining pawl after the completion of the stroke of the type lever.

9. In an escapement device for typewriters having a universal bar operatively associated with a type lever and a ratchet having teeth, the improvement which comprises a pivoted pawl bearer adapted to be actuated by said universal bar, a retaining pawl successively engaging said teeth pivotally mounted on said pawl bearer, said pawl being weighted so as to continue its movement after the completion of the forward movement of the said universal bar and release the engaged tooth after the completion of the stroke of the type lever.

10. An escapement device for typewriters and the like which comprises a. universal bar actuated by a type lever of the typewriter during the stroke of the said lever, a reciprocating pawl bearer, a retaining pawl movably mounted thereon adapted to receive an impulse from the universal bar, and a ratchet having teeth successively engaging said retaining pawl said retaining pawl having sufiicient inertia to continue its motion and release the ratchet after the completion of the stroke of the type lever, and means for returning the elements into their initial position.

FRITZ EIBERT. 

